Highly-dispersed platinum nanoparticles supported on vertically aligned carbon nanotube arrays were readily prepared by one-step liquid-phase process. The composites were grown on stainless-steel substrates via electric resistance heating of the substrate in an ethanol solution containing platinum-based organometallic complex as a nanoparticle precursor. The size of platinum nanoparticles on the nanotube surface can be controlled by changing the resistance heating time of the substrate. The nanoparticles were mainly formed on top part of the nanotube arrays, which is attributed to their characteristic reaction field for the formation, i.e., film boiling state. It is also interesting that the platinum nanoparticles were covered with low crystallinity carbon films and immobilized on the nanotube surface. Partial elimination of the films effectively brought electrocatalytic activity for the nanoparticles. This unique one-step process is valuable because it enables the simultaneous preparation of carbon nanomaterials and metallic nanoparticles in a short time. (C) 2017 Elsevier B.V. All rights reserved.